In his book Way to Wisdom, Karl Jaspers writes, “The source of philosophy is to be sought in wonder, in doubt, in a sense of forsakenness. In any case it begins with an inner upheaval, which determines its goal.” ~ (Chapter 2: “Sources of Philosophy”). I think this is correct. Till about 70,000 years ago the human beings were more or less like animals—they lacked the ability to doubt anything. But if people believe in everything that their senses tell them, there can be no philosophy. Philosophy came into being when language become advanced and human beings developed the ability to communicate to themselves and share with each other their doubts about the nature of the world. The first spark of philosophy must have been lit by the man who for the first time propagated the idea that the things that he and others see can be something else or may not even exist. But this implies that the idea that there is a reality outside the mind and that the world that we perceive through our senses is real has been gained through skepticism itself.